1. Field of the Invention
The present invention relates generally to a connection stent which connects the adjacent tissue of organs, such as the gall bladder, the pancreas, etc., of a patient so that the organs communicate with each other via the stent, thus forming a passage for an endoscopic operation, discharge or the shunting of bile or the like and, more particularly, to a stent for connecting adjacent tissues of the organs of a patient which includes a hollow cylindrical body ft/wed by weaving a superelastic shape-memory alloy wire in an overlapping manner, and wing parts provided by expanding respective opposite ends of the hollow cylindrical body outwards and turning the opposite ends inside out on bent portions so that the wing parts face each other so that they apply tension in a longitudinal direction of the hollow cylindrical body, whereby the wing parts elastically move inwards or outwards with respect to the longitudinal direction to automatically adjust the distance between the wing parts in response to the distance between the adjacent tissues of the organs or the thicknesses of walls of the organs and come into close contact with the adjacent tissues of the organs, so that the stent can be used regardless of the distance between the adjacent tissues of the organs or the thickness of tissue, and which can ensure not only the fixation of the stent to the organs but a seal that prevents leaks.
2. Description of the Related Art
Generally, stents are inserted into the internal organs, such as the gullet, stomach, duodenum, intestines, etc., of patients, thus forming passages.
Such a stent includes a hollow cylindrical body which is formed by weaving a superelastic shape-memory alloy wire in an overlapping manner such that a plurality of rhombic openings are formed in the hollow cylindrical body. Because the hollow cylindrical body can elastically expand and contract in the radial direction, when the stent is inserted into the internal organ of a patient, it can define a passage in the internal organ.
Recently, connection stents are used to allow access to an internal organ, such as the gall bladder or the pancreas, where it is difficult to directly conduct an endoscopic operation or an operation of discharging or shunting bile or the like.
That is, after piercing the adjacent tissues of the organs, such as the gall bladder, the pancreas, etc., a stent is inserted into the pierced holes so that the organs can communicate with each other.
FIG. 1 illustrates a conventional connection stent which was proposed in U.S. Pat. No. 6,620,122. As shown in FIG. 1, the conventional connection stent includes a hollow cylindrical body 2 which is formed by weaving a superelastic shape-memory alloy wire in an overlapping manner, and increased diameter parts 3 which are provided on opposite ends of the hollow cylindrical body 2 and have the shape of a dumbbell. After holes are formed through adjacent tissues 5 of the organs of a patient, the stent is inserted into the holes such that the increased diameter parts 3 are locked to the tissues 5 to prevent the stent from being removed therefrom, thus connecting the organs to each other.
However, the conventional connection stent is problematic in that the increased diameter parts 3 that are provided on the opposite ends of the hollow cylindrical body 2 make it difficult to insert the stent into the holes made in the tissues.
In addition, the distance between the increased diameter parts is fixed after the stent has been manufactured. Thus, when manufacturing the stent, the distance between adjacent tissues or the thicknesses of walls of the tissues must be taken into account. The stent may not be brought into elastic contact with the tissues, thus causing a gap between the stent and the tissue, making the discharge or shunting of bile or the like difficult.
Each edge of the increased diameter parts forms a right angle. This may damage the tissues of the organs.
FIG. 2 shows a stent which was proposed in US Patent 2009-281557 to overcome the problems of the stent of FIG. 1. In the stent of FIG. 2, a hollow cylindrical body 2 is formed by weaving an alloy wire such as a superelastic shape-memory alloy wire in a crossing manner. After the hollow cylindrical body 2 has been inserted into holes formed in the organs of a patient, increased diameter parts 4 are formed by pushing portions of opposite ends of the hollow cylindrical body 2 inwards with respect to the longitudinal direction so that the increased diameter parts 4 are locked to respective adjacent tissues 5, thus preventing the stent from being removed therefrom.
Although this stent can overcome the problem of the technique of FIG. 1 that makes it difficult to insert the stent into the holes in the tissues, because the distance between the increased diameter parts is also fixed, so that parts with an increased diameter must be formed to take into consideration the distance between adjacent tissues or the thicknesses of walls of the tissues. For these reasons, it is not easy to bring the parts with an increased diameter into elastic, close contact with the tissues so that a gap is formed between the stent and the tissues, making the discharge or shunting of bile or the like difficult.